1. Aim
To investigate if there is such a thing as
“the perfect squat technique” or does it all depend on what you are training
for?
2.
Intended audience
Primarily the article is written with
professional trainers and rehabilitation specialists in mind, although it would
also be of interest to anyone who enjoys training.
3.
Introduction
Narrow squat, wide squat, front
squat, back squat, feet turned out, feet turned in, bar high on the shoulders,
bar low on the shoulders, deep squat, don’t deep squat. The endless list of
conflicting theories on how to squat correctly leaves one feeling altogether
dizzy, with each fitness guru vehemently defending their technique as the only
way to perform a proper squat. However, very few online resources or trainers
back up their positions with actual scientific evidence. I certainly didn’t
when I first started out as a Personal Trainer. However, I intend to in this
article. I include my conclusion at the end of this article, but it is only that, my conclusion. You will have to decide
for your self.
4.
General Overview of the Research
It is important to note that for the purposes of this small article the research focuses mainly on the knee. Escamilla, 2001[1]
breaks the research down into the following key areas:
a.
Knee forces including
tibiofemoral shear force, tibiofemoral compressive force and patellofemoral
compressive force.
b.
Knee muscle activity focusing
on quadriceps, hamstrings, and gastrocnemius.
c.
Knee stability in the sagittal
plane and the frontal plane (i.e. anteroposterior and mediolateral
respectively).
This journal is primarily used in
this article as it already includes the majority of the studies I came across.
The rest of the data then looks at
foot position, knee position relative to the feet and various different squat
techniques. This data gives you information relating to the forces generated at
various joints and muscle recruitment.
I then reviewed research on the injuries
sustained from squatting, particularly focusing on Powerlifting and Olympic
lifting. This would then (in theory) give me the actual outcome of the relevant
lifting techniques on the health of the joints.
5.
So is there a Correct Foot Placement?
In short, it would appear not. The
angle of the foot would appear to have no relation to either which muscles are
targeted (i.e. Vastus medialis or lateralis) or how much they are recruited, as
is commonly believed amongst the training industry [1][5]. There also appears to be very little difference between wide or
narrow stance squatting. The only significant difference being that narrow
squats seem to elicit more muscle activity from the gastrocnemius [1] [2].
Where as wide squats, when performed as Powerlifters do, with a low bar position
on the shoulders and greater anterior trunk lean, seems to decrease the compressive
forces at the patellofemoral joint [1]. This is believed to be due to a more vertical position of the shin
when viewed in the sagittal plane (side on) thus decreasing the flexion angle
of the knee [4]. A greater angle of flexion at the knee, means greater
compressive forces at the patellofemoral joint. This information is important
if you already have an existing knee condition, however, it doesn’t necessarily
mean that a greater compressive force = greater damage to your knees. In fact
nobody really knows exactly how much compressive force and stress (force
divide/area) is damaging to the knee [1].
6.
Can the Knee Pass the Toe?
There is only one study I have been
able to find that addresses this particular question specifically. There have
been many fitness magazines and blogs that have been putting forward this idea
that the knee can and in fact should pass the toe. However, it would appear
this is only based on evidence from one study[3]. It
concluded that preventing the knee from moving forward (moving past the toe)
decreased the amount of stress at the knee, however, it shifted the stress to the
hips and lower back. As such they suggested that, to achieve appropriate joint
loading during the squat the individual should allow the knee to move slightly
past the toe.
Unfortunately some studies have shown
that the forward movement of the knee also increases shear forces at the
tibiofemoral joint [1].
7.
Which Form of Squat is the Best?
By form, I am referring to bar
placement and/or any machines used. Most literature looked at the front squat, back
squat, leg press and a few relating to single leg squat and body weight
squat. There was no evidence I could find on the above head squat. My focus is
on the back or front squat as these are the most common.
In essence it appears to depend on
what you are training for. Olympic lifters favour the front squat because it is
a key component of the lifts they perform. The nature of the lift tends to keep
the trunk more upright and often requires increased flexion angles at the knee.
This leads to slightly higher compressive forces on the patellofemoral joint [1]. Powerlifters use the back squat with a low bar position and more
forward trunk lean, the reason being to make greater use of the strong glutes and
erector spinae muscles. As such the knees don’t suffer the same compressive
forces (due primarily to decreased flexion angles at the knee[4]). The trade off however, is
increased force placed through the hip and lower back region [1].
It is also important to note that
some studies have found contrary to the above. They state that compressive forces at the
knee are greatest during the back squat. Therefore they advocate using the front
squat over the back squat for long term joint health and for those with
problematic knees[5].
Regarding Smith Machines and Leg
Presses, the studies show that these are not the best options for someone with healthy
knees. Smith machine squats increase the shear forces at the tibiofemoral joint
by 30 – 40 % when compared with free weight squats [1]. Shear forces are known
to be damaging to the knee and should always try to be reduced. Muscle activity
and knee forces are significantly less when using a Leg Press compared to free
weight barbell squats . Thus, Leg Press is less effective at muscle development[6] and as
such free weights should be utilised instead of the leg press in healthy, able
individuals.
8.
How Low Can You Go?
All the evidence suggests that to decrease the compressive forces at
both the tibiofemoral joint and the patellofemoral, you should only stick to the
“functional range” which is 0°- 50°[1]. However, as stated before, increased compressive force doesn’t = damage
to the knee. It is advantageous for athletes or those under training to work
the body throughout the ranges of motion they are likely to perform in
their chosen activities. So where does this leave us?
9.
What Do the Injuries Tell Us?
Nothing written above is really
conclusive evidence to squat one way or the other. There is also an inherent
issue with this type of literature as it attempts to predict the affects of
different forces on the body. This means they have to use various mathematical
models [1] that inevitably lead to
problems of accuracy. This leads us to look at the injuries sustained while
performing various techniques to see if this sheds any further light on the
situation. Below are brief summaries from various studies regarding injuries
sustained during weightlifting; either Olympic or Powerlifting.
110 elite lifters (Olympic and Power)
were surveyed, both male and female. 2.6 injuries per 1000hrs of activity were
noted. Most common were lower back injuries and shoulder injuries. It was also
noted that Olympic lifters sustained more lower back and knee injuries whereas
Powerlifters sustained more shoulder injuries[7].
245 competitive and elite
Powerlifters from 97 Powerlifting Clubs were surveyed. 1 injury per 1000 hrs of
activity were noted. The injury rate is
deemed as low when compared to other sports. The majority of the injuries were minor and did not affect training[8].
Information from a 6 year period from
the US Olympic Training Centre focused on US elite Olympic lifters. Injury
rates of 3.3 per 1000 hrs of activity were noted (combining both acute and
recurring injuries). The majority of injuries (68.9%) were strains or
tendonitis. 90.5% of injuries resulted in missing 1 day or less of
training. In conclusion the majority of injuries for Olympic lifters were overuse injuries (likely from training programs that were too intensive). The
rates of injuries were similar to those found in other sports[9].
25 experienced Olympic lifters were tested
for effects of osteoarthritis (general wear and tear) on their joints. The
study covered tibiofemoral joint, patellofemoral joint, hips, wrist, elbow and
shoulder. Significant degeneration was found in only five of the lifters (20%)
which is approximately half the number found in the general population. In
conclusion weight lifting (Olympic or Power) was not deemed to be a
pre-requisite to joint degeneration and may in fact improve stability and
health of the cartilage. Having said that, previously injured joints were more
susceptible to damage under heavy loads[10].
To put some perspective on these
injury rates Fuller, et al, 2007,
performed an extensive study into rugby, noting injury rates of 58 per 1000hrs
of activity[11].
10.
Conclusion.
The evidence suggests it is about
which technique is right for you and what you want to achieve, rather than
which is the best all round. One of the main factors is whether or not you have
an existing pathology in the knee. If you do, the evidence points to using quarter
squats (0º - 50º of knee flexion) to strengthen the site. Use slow, controlled
movements with feet approximately shoulder width apart and in a position of
turn out that is comfortable to you. Care should be taken for those with an
injured PCL (posterior cruciate ligament) as slightly more strain is placed on
the PCL compared to the ACL. However, squats are still a viable exercise for
PCL rehabilitation under lighter loads.
For those of you who aren’t injured, there are 2 options:
1. You adhere to the evidence that attempts to predict the effects of squatting on the knee. In this case you would perform heavy, quarter squats (0º - 50º flexion at the knee), feet approximately hip width to shoulder width apart, turned out in a comfortable position for you. This would limit the amount of wear and tear on the tibiofemoral and patellofemoral joints, and the quadriceps and patella tendons. It would encourage compressive forces within the knee, which in turn improves stability. It would also rule out any over stretching of the ligaments and capsule surrounding the knee.
1. You adhere to the evidence that attempts to predict the effects of squatting on the knee. In this case you would perform heavy, quarter squats (0º - 50º flexion at the knee), feet approximately hip width to shoulder width apart, turned out in a comfortable position for you. This would limit the amount of wear and tear on the tibiofemoral and patellofemoral joints, and the quadriceps and patella tendons. It would encourage compressive forces within the knee, which in turn improves stability. It would also rule out any over stretching of the ligaments and capsule surrounding the knee.
Or....
2. You take your lead from the evidence
based around the outcomes of the training (i.e. the injuries found in
Powerlifting and Olympic lifting). In this case you would use the techniques
employed by either discipline depending on what you are trying to achieve. The
evidence suggests there is no increase in injury risks from performing wide or
deep squats, front or back. The key is a progressive training program with
appropriate recovery to avoid over use injuries and bring about the correct
adaptations in the body.
Personally, I subscribe to the latter
option. It is evidence based on actual data that has definitely occurred, not
predictions of what might happen. I enjoy mixing my training between each of
the disciplines and I’m currently working on, deadlifts, clean and snatch. Therefore
the majority of squatting actions I perform are those in the front squat
position where by my knees travel slightly past my toes at some points during
different lifts. As for my clients it completely depends on 3 things:
a.
What they are comfortable with.
b.
What they are capable of (i.e.
injuries or disabilities).
c.
What their goals are.
These factors should always be considered
when writing your own programs.
11.
Future Articles.
Further articles leading on from this
will include program design, periodization and appropriate recovery to avoid
injuries and gain consistency in your training.
All the best
Gregory Hunt
12.
References
[1] Escamilla R. F., et al. Knee biomechanics of the dynamic squat
exercise. Journal of American College of Sports Medicine. 2001. http://www.mlmixrun.com.br/artigos/Knee_biomechanics_of_the_dynamic.pdf
[2] Signorile
J.F., et al. Effect of Foot Position on the Electromyographical Activity
of the Superficial Quadriceps Muscles During the Parallel Squat and Knee
Extension. The Journal of Strength and Conditioning. Aug 1995; 9, (3). http://journals.lww.com/nsca-jscr/Abstract/1995/08000/Effect_of_Foot_Position_on_the_Electromyographical.11.aspx
[3] Fry A.C., Smith J.C., Schilling B.K. Effect of knee position on
hip and knee torques during the barbell squat. J Strength Cond Res. Nov
2003;17(4):629-33. http://www.ncbi.nlm.nih.gov/pubmed/14636100
[4] Switon P. A., et
al. A Biomechanical Comparison of the Traditional Squat, Powerlifting
Squat, and Box Squat. Journal of Strength and Conditioning. Jul
2012; 26 (7); 1805–1816 http://journals.lww.com/nsca-jscr/Abstract/2012/07000/A_Biomechanical_Comparison_of_the_Traditional.10.aspx
[5]Gullett J.C., et al. A biomechanical comparison of back and front squats
in healthy trained individuals. J Strength Cond Res. Jan 2009;23(1):284-92. http://www.ncbi.nlm.nih.gov/pubmed/19002072
[6] Escamilla R.F., et al. Effects of technique
variations on knee biomechanics during the squat and leg press. Journal of the
American Sports College of Medicine. 2001.
http://www.treinamentoesportivo.com/wp-content/uploads/2012/10/ARTIGO-AGACHAMENTO-01.pdf
[7] Raske A., Norlin R. Injury
Incidence and Prevalence among Elite Weight and Power Lifters. American Journal
of Sports Medicine [Website] http://ajs.sagepub.com/content/30/2/248.short#aff-3
[8] Siewe
J., et al. Injuries and Overuse Syndromes in
Powerlifting. International Journal of Sports Medicine. 2011;
32(9): 703-711 https://www.thieme-connect.com/ejournals/abstract/10.1055/s-0031-1277207
[9] Calhoon G., Fry A.C. Injury Rates and Profiles of
Elite Competitive Weightlifters. Journal of Athletic Training. Jul-Sep 1999; 34(3): 232–238. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1322916/
[10] Fitzgerald B., Mclactchie G.R. Degenerative
Joint Disease in Weight Lifters Fact or Fiction?. Brit J. Sports Med. Aug 1980;
14(2&3): 97-101 http://bjsm.bmj.com/content/14/2-3/97.full.pdf+html?sid=063a5648-46f2-42c5-9459-a37a2c41aeee
[11] Fuller C.W., et
al. Contact events in rugby union and their propensity to cause injury. Br J
Sports Med. Dec 2007 ; 41(12): 862–867. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2658974/
